Vacuum tube



VACUUM TUBE Filed July 5, 1926 3 Sheets-Sheet l VWTNESSES: INVENTOR W, Samuel/ 1 Kimner: I BY 5 I I 2 AIFTORNEY Jan. 5, 1932. M KlNT NER 1,839,562

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ll 7 0 O I I I 1 1 i a i i 33 i az 32 1 g I 1 1 o o l I l WITNESSES INVENTOR Samuel M/(z'nzner:

- ATTbRNEY S. M. KINTNER Jan. 5, 1932.

VACUUM TUBE Filed July 5, 1926 3 Sheets-Sheet 3 INVENTOR Samuel M Kmzner.

AT'IZORNEY WITNESSES:

Patented 5, 1 932 UNITED STATES PATENT OFFICE SAMUEL M. KHVTNER, OI PITTSBURGH, PENNSYLVANIA, ASSIGNOB 'I'O GHOUSE ELECTBIC'& MANUFACTURE G COMPANY, A. CORPORATION OF PENNSYLVANIA vacuum TUBE Application filed July 3, 1928. Serial Ho. 120,436.

My invention relates toelectrode mountin for vacuum tubes and it has among its ob ects the provision of improved anchoring means for the upper ends of the grid and plate supporting structure which enables the completlon of the grid and cathode assembly prior to the mounting of the plate around the grid-cathode structure.

In the accompanying drawings, Fig. 1 is a perspective view of a three-electrode vacuum tube in accordance with my invention, with portions of the Walls of the tube and the plate cut away;

Fig. 2 is an elevational view of the electrode assembly of the tube shown in Fig. 1,

with the plate removed,

Fig. 3 is a top view of the lower insulating suplport used in the electrode assembly shown in ig. 2,

Fig. 4 is a side elevational view of the electrode assembly shown in Fig. 2.

Figs. 5 and 6 are elevational and top views, respectively, of I the plate used in the tube shown in Fig. 1,

Fi 7 is an elevational view of an electrode assembly embodying a modification of my invention, and

Fig. 8 is a perspective view of an electrode assembly embodying a further modification of my invention. 4

In Fig. 1 is shown a three-electrode tube 1, to which my invention is preferably applied. This type of tube is chiefly used for power amplifiers and power oscillators having a rating of 50 to 100 watts. The electrode assembly used in the tube shown in the drawings has been produced after numerous designs and experiments, it being necessary to support a relatively heavy structure in a manner which will exclude mechanical vibration of the electrodes. Since the tube is manufactured in large quantities, it is of utmost importance to so arrange the electrode mounting as to permit quick and cheap assembly of the tube with accurate spacing between the several electrode elements in order to obtain a product of uniform characteristics.

As shown in the drawings, the electrode mounting comprises a metallic sleeve or band 2, clamped around a. cylindrical reentrant stem 3, of the glass tube 1. Two main standards 4 are welded, or otherwise secured, to two diametrically opposite portions of the metallic sleeve 2, and extend in parallel relationship upwardly into the tube. The mam standards carry a cross-shaped main insulatmg support 6, of porcelain for instance. The bar of the cross piece 6 which is supported by the main standards has vertical perforations which are slid over the two main standards from the top thereof, the standards belng somewhat flattened atthe point where the bottom of the cross piece 6 is to rest. The upper portion of the stem 3 carries a press 9 into which are fused threelead-in wires 10, of tungsten, for instance, which'terminate somewhat below the lower surface of the cross bar disposed in the plane perpendicular to the plane of the two standards, that is in the plane of the press.

From the last mentioned bar of the supporting cross, two auxiliary standards or posts 11 extend upwardly, being suitably held in vertical perforations in the bar. The auxiliary standards 11 carry a grid in the shape of a helix 12 of fine wire, wound therearound and suitably secured thereto. Between the grid standards 11, and in spaced relation thereto and to each other, the cross bar carries three filament supporting standards 13, 14 and 15 to which are secured the lower extremities of an inverted W-shaped cathode filament 16 vertically mounted in the space between the grid wires.

The upper ends of the auxiliary grid posts are held in fixed spaced relation with respect to each other by means of an upper insulating bar 21, which constitutes in connection with the two grid posts, and the lower cross bar 90 upon which the grid posts are mounted, a substantially rigid grid frame. The upper insulating bar 21 of the grid frame is provided with two perforations 22 into which are inserted resilient filament hooks 23 for 95 holding the upper bights 24 of the cathode filament 16. In the preferred construction shown in the drawings, the upper ends of the filament hooks 24 form spring helices 26 permitting the hooks to be pushed downwardly for engaging or catching the filament bights when mounting the same.

Over the grid-cathode structure, assembled as described above, is slipped the anode 31 shown in detail in Figs. 5 and 6. The anode comprises two U-shaped plate members 32 having at their ends laterally projecting extensions 33 abutting against each other, thus forming an oval tubular plate unit having sufiicient clearance to slide over the upper insulating bar 22 of the completely assembled grid-cathode unit. The lateral extensions 33 of the plate are provided, at their ends, with grooves constituting vertical sleeve 34, adapted to fit over the main standards 4, which extend from the stem of the tube. The two halves of the plate are held together by means of two end frames 35, which are suitably fixed or riveted to the plate members.

After the plate is slipped over the grid structure, with the sleeves 34 slid over the main standards 4, the assembly is completed by joining the two upwardly projecting ends of the main standards 4 by means of a bar 41 which is then riveted, bolted, or otherwise secured to the upper grid-frame insulating bar 21 at the point where they cross each other. In the preferred construction shown in Figs. 1 to 4, the upper cross bars 21 and 41 are notched at the portions where they cross etich other so that they lie substantially in one ane.

p The construction described above thus provides two frame units, one constituted by the stem sleeve 2 in conjunction with the main standards 4, the plate 31 and the top cross bar 41, and a grid-frame unit 10, Hand 12 on which the grid and cathode is mounted. Since the two frames are rigidly braced by the upper and the lower cross bars, the location of the several electrode elements is definitely fixed with respect to each other, assuring tubes of uniform characteristics.

In the prior art construction of such tubes, the upper bracing or anchoring bars 21 and 41 were made in a single unit and, accordingly, the grid frame could not be finally assembled until after the plate 31 has been slipped into position. A single-unit cross piece was then placed on top of the standards and, after the plate was thus located in its final position, the filament supporting hooks were pressed down to catch the upper bights 24 of the cathode filament.

This operation was very inconvenient since the filament was entirely out of sight and covered by the tubular anode whereby the operation of catching the upper filament extremities by the hooks 23 was very laborious and, more or less of a hit-or-miss proposition. As a result thereof, many tubes were damaged in the course of the assembly, with a consequent large waste in the manufacture. In addition, the operation required an abn0rmally long time and thus additionally increased the'cost .of manufacture of the tubes.

By splitting the upper bracing or anchoring cross into two separate bars 21 and 41, for the grid and plate frame, respect1vely, as shown in my improved constructlon, thedllhculties in mounting the'upper filament bights have been radically removed.

In accordance with my invention, the grid frame is completely assembled, with the upper frame bar 21 put into place before the plate 31 is placed in position. The filament is then mounted inside the grid frame and the upper bights 24 of the filaments are suspended on the hooks 23 while being in full view. After the grid and cathode have been fully completed the plate is slipped into place and the upper plate-frame member 41 is mounted in position and secured to the upper grid frame member 21 in order to stiffen the structure. The electrode assembly which is thus obtained has all theadvantages of rigidity and stiffness that were present in the prior-art construction described above. However, the simple expedient of splitting the upper bracing member into two parts, to permit the completion of the grid-cathode structure while in full view, resulted in surprisingly large savings in the time, as well as in the cost, of manufacture of such tubes.

The features of my invention are, of course, not limited to the particular arrangement described hereinabove but may be embodied in many other constructions. Thus in the modifications of my invention shown in Fig. 7 an assembly of a three-electrode tube comprises a lower insulating supporting bar 51 which is held by four lead-in wires 52, 53, 54 and 55 that are fused in the press 56, extending from the stem 57 of the tube. The supporting bar 51 carries a pair of grid standards or posts 61 which are joined at the top by an upper grid-frame member 62. The grid standards carry the usual wire grid 63, and a W-shaped cathode filament 64 is mounted between the grid standards as in the construction shown in Fig. 1 of the drawings. The lower supporting member 51 carries two additional plate supporting posts or standards 66 upon which a plate 67 is mounted. An upper bracing member 68 is fixed on the top of the ends of the grid and plate standards to brace the same with respect to each other.

The modification of my invention shown in Fig. 8 is in every respect similar to that of Fig. 1, except that the lower supporting cross, upon which the electrodes are mounted, is also split into two bars 71 .and 72, similar to the two-part cross piece used at the top of the electrode structure in Fig. 1. The cathode and grid may thus be assembled as a separate complete frame unit comprising the upper and lower bracing bars 21 and 7 2, and the side posts 11, the completed grid-cathode structure being then mounted between the main standards 4, on which the plate is supported.

The above described modifications will suggest to those skilled in the art, numerous other structures whereby the underlying idea of my invention, namely electrode mountings which enable the completion of the assembly of the elements which are covered by the tubular plate before the plate is located in the position where it obstructs the view to the interior elements of the tube, may be practically carried out.

I claim as my invention:

1. In an electron discharge device of the type having a tubular plate and a cathode mounted within said plate, an electrode support comprising a pair of plate supporting standards, a pair of auxiliary standards extending in the interior of said tubular plate, a first bracing member fixed to the upper ends of said auxiliary standards, means for insulatingly supporting a cathode from said bracing member and a second bracing mem ber joining the upper ends of said plate supporting standards to said auxiliary standards, the structure comprising the auxiliary standards and the first bracing member being of such dimensions as to fit into the opening in said plate to permit the same to be slid over the completely assembled cathode supporting structure.

2. In an evacuated electron discharge device of the type comprising a stem and an assembly of electrodes supported on said stem, a pair of main standards extending in spaced parallel relationship from said stem, a bottom insulating block supported by said standards and bracing the same, a pair of grid standards extending from said block in a plane perpendicular to the plane of said main standards, a cathode supporting means mounted on said insulating block between said grid standards, an insulating top block rigidly holding the upper ends of said grid standards, cathode supporting means mounted on said top block, a grid supported by said grid standards, a cathodemounted upon said cathode supporting means, a plate structure supported by said main standards and substantially fully covering the space between said grid standards, said plate structure fitting over said insulating block, and additional bracing means secured to the u per ends of said main standards and to said top block.

3. In an electrical space-current discharge apparatus comprising an evacuated envelope having a stem, and a plurality of electrodes supported on said stem, a metallic sleeve surrounding said stem, a pair of upwardly extending standards secured to substantially diametrically opposite points on said sleeve, a substantially rectangular grid frame, means for insulatingly supporting the bottom end of said frame upon said standards,'a cathode insulatingly supported by said grid frame,

a tubular plate enclosing said grid frame and slidable thereover an a bracing member joining the upper ends of said standards, and means for securing the end of said grid frame to said upper bracing member.

4. In an electrical space-current discharge apparatus comprising an evacuated envelope having a stem, and a plurality of electrodes supported on said stem, a metallic sleeve surrounding said stem, a pair of upwardly extending standards secured to substantially diametrically opposite oints on said sleeve, a substantially rectangular grid frame, means for insulatingly supporting the bottom end of said frame upon said standards, a cathode insulatingly supported by said grid frame, a tubular plate enclosing said grid frame and slidable thereover, a bracing member joining the upper ends of said standards and locking said plate in place about said grid frame, and means for securing the end of said grid frame to said bracing member.

5. An electron discharge device comprising an evacuated envelope, a re-entrant stem in said envelope, a press on the top of said stem, leading in wires welded into said press, a metallic sleeve clamped to said stem, a pair of main metallic wire standards secured to diametrically opposite points on said sleeve in a plane perpendicular to said press, a lower insulating supporting block mounted on said main standards, and holding the same together, said supporting block having a pair of lateral projections in a direction perpendicular to the plane of said standards, a pair of auxiliary standards mounted on said lateral projections and extending parallel to said main standards, an upper insulating block joining the upper ends of said auxiliary standards, filament supportin hooks held by said two insulatin blocks, a lament strung on said books, a tu ular plate enclosing the space around said cathode and having sleeves fitting over said main standards, said plate being slidable over said upper insulating block, and the auxiliary standards, and an additional anchoring-member joining the top portion of said main standards to said top block.

6. An electrode mounting for vacuum tubes comprising a pair of main standards and an anchoring member holding the upper ends of said standards in spaced relation with respect to each other and constituting therewith a substantially rectangular frame, a tubular plate supported by said main standards, a cathode supporting frame within said tubular plate, a cathode mounted on said supporting frame, means for insulatingly supporting the lower end ofsaid cathode supporting frame on said main standards, and means for anchoring'the upper end of said cathode supporting frame to the upper ends of said main standards.

7. In' an evacuated s ace-current discharge device, an electro e assembly comprising a pair of main standards, a member joining the upper ends of said standards and constituting therewith a closed frame, a second frame supported by said first-mentioned frame, a cathode and grid structure mounted on saidsecond frame, and a plate surrounding said last-mentioned frame and supported on said main standards, said plate being slidable over said main standards and second frame and cathode and grid structure.

8. In an evacuated electron discharge device, an electrode support comprising a stem, a pair of main standards extending from said stem, an upper bracing member 10in the ends of said standards and constitutin tierewith a substantially rectangular mam electrode supportin frame, a second frame disposed within sa1d main frame, a grid struc-\ ture wound on said second frame, a cathode insula-tingly supported by said second frame within said grid, and a tubular plate electrode enclosing said second frame and slidable thereover, and means for insulatingly supporting the upper and lower ends of said second frame from said first-mentioned frame.

In testimony whereof, I have hereunto subscribed my name this 24th day of June, 1926.

SAMUEL M. KINTNER. 

